Clinical experience with diltiazem in Japan

Interpretation and application of world-wide safety data on diltiazem

The safety of medicinal agents being introduced into the marketplace is of growing concern to consumers, health care providers, and regulatory agencies. Although there are ever increasing efforts to improve techniques for testing drugs, and for anticipating and confirming possible adverse effects, arrangements for monitoring and detecting adverse drug reactions are far from satisfactory. Some factors which need to be understood in order to appropriately interpret data include: maturation processes; pretesting affects, measuring instruments affects; selection bias; and the affects of differential experimental mortality. A safety profile has been presented for the calcium entry blocker diltiazem hydrochloride. Efforts were made to focus attention upon the source of safety information as it relates to the quality of the report. The data presented suggests that diltiazem hydrochloride has a low incidence of adverse experiences.

Identification of the Atypical L-Type Ca2+ Channel Blocker Diltiazem and Its Metabolites As Ghrelin Receptor Agonists

Using a high-throughput functional screen, the atypical L-type Ca2+ channel blocker diltiazem was discovered to be an agonist at the human ghrelin (GHSR1a) receptor. In cellular proliferation, Ca2+ mobilization, and bioluminescence resonance energy transfer (BRET-2) assays, diltiazem was a partial agonist at GHSR1a receptors, with 50 to 80% relative efficacy compared with the GHSR1a peptide agonist GHRP-6, and high nanomolar to low micromolar potency, depending upon the assay. Seven of the known primary metabolites of diltiazem were synthesized, and three of them (MA, M1, and M2) were more efficacious and/or more potent than diltiazem at GHSR1a receptors, with a rank order of agonist activity of M2 > M1 > MA > diltiazem, whereas M4 and M6 metabolites displayed weak agonist activity, and the M8 and M9 metabolites were inactive. Binding affinities of diltiazem and these metabolites to GHSR1a receptors followed a similar rank order. In vivo tests showed that diltiazem and M2 each stimulated growth hormone release in male Sprague-Dawley neonatal rats, although to a lesser degree than GHRP-6. Thus, diltiazem and chemical analogs of diltiazem represent a new class of GHSR1a receptor agonists. The possible contributions of GHSR1a receptor activation to the clinical actions of diltiazem are discussed in the context of the known beneficial cardiovascular effects of ghrelin.

The Diltiazem Different Doses Study--a dose-response study of once-daily diltiazem therapy for hypertension

The objective was to evaluate the dose-related efficacy/tolerance profile of 240, 300, 360, and 420 mg diltiazem slow-release, once-daily (OD) doses, with emphasis on the 300 mg dose. The study was randomized and double-blinded with a 36-week parallel, two-branched, cross-over design after a single-blind, run-in period of 4 weeks on placebo and 6 weeks on 300 mg diltiazem OD. Each branch included six 6-week active treatment periods with 180, 240, and 300 mg tablets, one or two tablets OD. Participants were men and postmenopausal women, aged 40-70 years, with uncomplicated primary hypertension (WHO stages I and II) and a supine diastolic blood pressure of 95-115 mm Hg in the absence of antihypertensive medication. A total of 138 patients from various clinics participated in the study. All were included in the intention to treat analysis, and 117 patients were included in the per protocol analysis. Criteria for evaluation were blood pressure, heart rate, and response rate, as well as plasma diltiazem and metabolite M1 concentration before morning dose. Well-being of the patients and adverse events were recorded. Electrocardiogram and standard laboratory tests were obtained. Analysis of variance was used for statistical calculations. Supine blood pressures and response rates in the per protocol analysis were 161.2/97.0 for placebo (29.1%), 155.2/ 92.8 for 240 mg (54.7%), 153.8/91.6 for 300 mg (55.6%), 155.5/92.0 for 360 mg (59.0%), and 152.0/90.5 for 420 mg (63.2%) of diltiazem OD. The intention to treat analysis was very similar to the per protocol analysis. There was a small but statistically significant decrease in heart rate for all doses of diltiazem OD compared to placebo. A linear relationship existed between the dose and the plasma concentration of both diltiazem and metabolite M1, as well as a dose-response relationship. Diltiazem OD in the dose range 240-420 mg was generally well tolerated and not differently perceived from the placebo treatment except for ankle edema (2-6%). The study shows that OD diltiazem is significantly superior to placebo for mild to moderate hypertension and that the effect is large enough to be clinically valuable. It also shows that there is a linear dose-response relationship for diltiazem between 240 and 420 mg.

Effect of diltiazem on silent ischemic episodes, plasma bradykinin and prostaglandin metabolism

Plasma bradykinin and prostaglandin metabolism are related to the anginal pain modulating system in patients with ischemic heart disease. We carried out a placebo controlled single blind test of diltiazem (30 mg three times a day) in 15 patients with chronic stable angina. The effect of diltiazem was evaluated by exercise treadmill testing and 48-h ambulatory electrocardiographic monitoring. Plasma bradykinin, thromboxane B2, and 6-keto-prostaglandin F1 alpha levels were determined by radioimmunoassay prior to and during diltiazem therapy. Diltiazem significantly increased the exercise time and reduced episodes of angina. Diltiazem, however, did not appreciably improve either the frequency of silent myocardial ischemic episodes or the total duration of the silent myocardial ischemic episodes. Diltiazem also tended to decrease plasma bradykinin, thromboxane B2, and 6-keto-prostaglandin F1 alpha levels. When ischemic episodes on ambulatory electrocardiographic monitoring are categorized according to heart rate change at the onset of episode (type A, preceded by heart rate increase > or = 5 beats/min; type B, no preceding heart rate increase), diltiazem was only effective on type A ischemic episodes as well as on symptomatic ischemia. Further, bradykinin was significantly decreased by diltiazem only in patients with exercise-induced silent ischemia or no exercise-induced ischemia, while the thromboxane B2/6-keto-prostaglandin F1 alpha ratio was unaffected by the administration of diltiazem. Thus, silent and symptomatic ischemia may be associated with different bradykinin and prostaglandin responses.

Diltiazem overdose: case report and review

We present a case of diltiazem overdose in which the patient ingested 4.2 grams in an apparent suicide attempt. He arrived in the emergency department two hours postingestion with a blood pressure of 60/40 torr and a heart rate of 62 beats/min in a junctional rhythm. Intervention included activated charcoal, gastric lavage, intravenous fluids, calcium (both chloride and gluconate), dopamine, and atropine with improvement in vital signs. Diltiazem levels were obtained and half-life calculated. This ingestion is one of the largest reported in the literature and is remarkable in that the patient recovered without pacing or other extraordinary measures. All eight previously published cases of diltiazem overdose, including all unpublished reports to the manufacturer, are reviewed and their management strategies examined. Successful treatment in which recovery has occurred in less than 48 hours, includes pressors, calcium, glucagon, pacing, and charcoal hemoperfusion. A strategy for emergency physicians to use when approaching this problem is suggested from the review.

Reports of erythematous macular skin eruptions associated with diltiazem therapy

Diltiazem is a commonly prescribed calcium-channel antagonist for hypertension and ischemic heart disease. The incidence of rash associated with diltiazem therapy is reported to be 1.3 percent. We describe two patients who developed erythematous, macular skin eruptions, approximately two weeks following institution of diltiazem. The skin eruptions resolved after symptomatic treatment and the patients received further therapy with another calcium-channel antagonist. Diltiazem-associated skin eruptions are a rare adverse effect; however, the incidence of rash may occur more frequently than reported in postmarketing surveillance studies.

Behavioral effects of diltiazem injected into the paraventricular nucleus of the hypothalamus

The calcium channel inhibitor diltiazem is widely used as a medication for cardiovascular diseases. Some side effects have been reported after its administration, including changes in activity (apathy or hyperactivity) and feeding behavior (anorexia). Previous experiments have found that local administration of various peptides into the paraventricular nucleus of the hypothalamus can have profound effects on these two behaviors. In the present study, effects of local infusions of diltiazem into the paraventricular nucleus on locomotor activity and food intake have been tested. A marked hyperactivity, greater than the hyperactivity caused by intraperitoneal injection of amphetamine was produced. Feeding behavior was not affected one hour after the infusions but intraventricular diltiazem infusions decreased feeding behavior. It is concluded that the paraventricular nucleus of the hypothalamus has an important role in the regulation of locomotor activity and that diltiazem can act at this level to produce behavioral changes.

Calcium channel blockers and cardiac surgery

Calcium channel blockers have an important role in the pharmacotherapy of cardiovascular disorders. These agents act by inhibiting the slow inward current into excitable cells, exert direct negative inotropic, chronotropic, and dromotropic activity, and are potent vasodilators. These direct effects are modified by reflex autonomic stimulation and by pathologic states. Serious adverse effects of the calcium channel blockers are most frequently observed in patients with ventricular dysfunction, conduction system disease, or concomitant beta blockade. Calcium channel blockers are indicated in the treatment of angina pectoris, supraventricular arrhythmias, and hypertension. The use of these agents in patients with hypertrophic cardiomyopathy, congestive heart failure, and pulmonary hypertension is investigational. The calcium channel blockers are gaining increased importance in the management of patients undergoing cardiac surgery. Verapamil is indicated for the treatment of post-cardiac-surgical atrial flutter and fibrillation; however, the calcium antagonists are not effective as prophylaxis against postoperative supraventricular arrhythmias. Laboratory studies have shown that drug interactions exist between calcium channel blockers and inhalational anesthetics and nondepolarizing neuromuscular blocking agents; clinical studies have demonstrated that these interactions are rarely significant. Perioperative coronary spasm can be effectively treated with the calcium channel blockers. The timing of calcium antagonist withdrawal prior to surgery is controversial, but continuation of therapy until surgery is usually safe. The clinical significance of platelet function inhibition by the calcium antagonists is unknown. Protection of ischemic myocardium by calcium channel blockers has been demonstrated. Important interactions between the calcium antagonists, hypothermia, and the ionic constituents of cardioplegia require further study before the role of these agents as adjuncts to clinical cardioplegia is defined. Expanded indications and the introduction of new calcium channel blockers will result in increased use of these agents in the future.

Diuretics versus calcium-channel blockers in systemic hypertension: a preliminary multicenter experience with hydrochlorothiazide and sustained-release diltiazem

The safety and efficacy of sustained-release diltiazem 120 to 180 mg, 2 times a day, were compared with hydrochlorothiazide 25 to 50 mg, 2 times a day, and the combination of diltiazem and hydrochlorothiazide in 56 patients with mild to moderate hypertension (supine diastolic blood pressure between 95 and 114 mm Hg) using a placebo-controlled, parallel-design protocol. Data from an additional 21 patients were evaluated for safety only. The data reported herein represent the preliminary experience from a larger 200-patient multicenter study. All patients received placebo for 4 weeks, followed by either hydrochlorothiazide or diltiazem titrated to achieve a diastolic blood pressure reduction of greater than or equal to 10 mm Hg to reach a goal supine diastolic blood pressure of less than 90 mm Hg. Patients not achieving the treatment goal received hydrochlorothiazide plus diltiazem. At week 14, on maintenance monotherapy, diltiazem and hydrochlorothiazide produced comparable reductions in blood pressure from placebo baseline (160.3 +/- 24.3/101.7 +/- 5.5 to 145.2 +/- 24.1/89.8 +/- 7.4 mm Hg with diltiazem, 156.0 +/- 15.6/103.7 +/- 4.7 to 134.1 +/- 12.5/89.2 +/- 9.5 mm Hg with hydrochlorothiazide, p less than 0.001 for both). Diltiazem and hydrochlorothiazide achieved goal blood pressure in 42% and 45% of patients, respectively. The effects in responders were sustained for 6 months. In patients who did not achieve the treatment goal, 63% responded to diltiazem plus hydrochlorothiazide.No clinically significant postural hypotension was observed on any regimen. Heart rate was slightly lower with diltiazem than with hydrochlorothiazide. Adverse effects were minimal with diltiazem, hydrochlorothiazide and diltiazem plus hydrochlorothiazide but more hypokalemia occurred with hydrochlorothiazide.(ABSTRACT TRUNCATED AT 250 WORDS)